A guide to revising the validity of digital signatures in the iLovePDF Desktop App

When you’re dealing with important documents—contracts, agreements, invoices—it’s not just about what’s written on the page. You also want to be sure those files haven’t been tampered with. That’s where digital signatures come in. But what happens when you're not sure if that signature is valid?

If you've opened a PDF in the iLovePDF Desktop app for Windows and seen a digital signature message you didn’t fully understand, you're not alone. This guide will walk you through how to interpret those messages and check if a signature is really valid—without needing a computer science degree.

Key takeaways:

• Digital signatures ensure your PDF hasn't been altered and confirm who signed it
• iLovePDF Desktop for Windows lets you verify and revise digital certificates with just a few clicks
• You'll learn what common messages in the digital signature section actually mean
• We’ll cover how to check if a certificate is expired, revoked, or simply untrusted
• You’ll also find out how to add or edit a certified digital signature

What makes a digital signature valid

Not all digital signatures are created equal. For a digital signature to be considered valid, it needs to meet certain legal and technical standards. These standards vary depending on your location, but many countries follow frameworks like eIDAS (Europe), ESIGN and UETA (United States), or similar national regulations.

In simple terms, a valid digital signature must:

• Prove who signed the document (authenticity)
• Show that the content hasn’t been changed since it was signed (integrity)
• Be linked to a trusted certificate authority or digital ID (trust)

This process usually involves cryptographic certificates and timestamping, both of which are built into tools like iLovePDF’s Digital Signature feature. That’s why it’s trusted by international businesses, government offices, and everyday users alike. Whether you're signing a freelance contract or a corporate agreement, iLovePDF helps ensure your digital signature meets these legal standards.

The role of digital certificates in e-Signing 

Every digital signature is backed by a digital certificate. Think of a certificate as your electronic ID card. It’s what tells others, “Yes, this signature really is from this person or organization.”

Certificates are issued by trusted organizations known as Certificate Authorities (CAs), and they have expiration dates just like passports. If anything about the certificate seems off—expired, revoked, or not from a recognized source—your PDF app will flag it.

How to revise a digital signature in iLovePDF Desktop

If you’re reviewing a signed document and want to check whether the digital signature is valid, iLovePDF Desktop gives you a quick and clear way to do it.

Here’s how:

This helps you understand not just if the signature is valid, but why. It's especially helpful if you're dealing with legal, financial, or sensitive documents that require proper compliance.

How to add or edit a digital signature

Need to sign a document with a digital certificate? Or maybe update an existing one? iLovePDF’s Desktop App makes it easy to add or edit legally binding digital signatures.

To add a new digital signature:

Already have a signature but need to make changes?

• Click on the existing signature in the document
• Select Edit to update it, or Add Certificate to attach a Digital ID
• You can also create a new Digital ID or use a Signature Creation Device if required

Whether you're sending contracts, official letters, or forms, iLovePDF helps you do it with confidence—and compliance.

Revising digital signatures in iLovePDF Desktop

iLovePDF Desktop makes it easy to check, verify, and revise digital signatures. Here's what you might see in the app—and what those messages mean in plain language.

Common status messages and what they mean

Certificate is valid (OCSP)

The certificate is still good and hasn’t been revoked.

Certificate revoked

The certificate has been canceled by the authority that issued it—don’t trust this one.

No chain source to trusted anchor

The certificate doesn’t connect back to a trusted authority. The app can’t confirm it’s safe.

Status cannot be determined

There’s not enough info to confirm if it’s valid or not. Use caution.

Valid certificate (CRL check)

The certificate passed a revocation list check—still valid.

Trusted anchor or higher certificate

It’s a high-level certificate, like a root certificate, which doesn’t need revocation checks.

Untrusted root certificate

The app doesn’t recognize the source of the certificate, so it might not be safe.

What do all those terms in the "Details" tab mean?

When you click into a signature's details, you’ll see some technical terms. Here’s a simple breakdown:

Subject / Issuer

Who the certificate is for, and who issued it.

Start of validity / End of validity

When the certificate starts and stops being valid.

Signature algorithm

The method used to secure the signature.

CRL Distribution Point / OCSP

Where the app checks if the certificate was revoked.

Key usage / Extended key usage

What the certificate is allowed to do—like signing documents or verifying identities.

You don’t have to memorize these, but it’s helpful to know what you're looking at.

Why your certificate might not be valid

Sometimes, a digital signature fails the verification check—and it’s not always obvious why. Here are the most common reasons your certificate might be flagged as invalid, along with what each one means.

The certificate has expired

Digital certificates come with expiration dates. If the certificate has passed its validity period, it can no longer be trusted—even if it was valid at the time of signing. Always check that the certificate is current before relying on it.

The certificate was revoked

A certificate can be revoked by the issuing authority for several reasons—such as if the signer’s private key was compromised or if they’re no longer authorized to sign documents. Once revoked, the certificate is no longer considered valid, regardless of its expiration date.

The issuer isn’t trusted

If the certificate was issued by an authority that’s not recognized by your system or signing tool, it won’t be trusted. Only certificates from known and approved Certificate Authorities (CAs) are considered reliable.

The certificate chain is incomplete

Digital certificates are part of a “chain” that leads back to a trusted root certificate. If part of that chain is missing, your system can’t verify the certificate properly. This breaks the chain of trust and invalidates the signature.

Signer details don’t match

If the information in the certificate doesn’t match the signer’s identity—such as name or email address—your app may flag it as suspicious. Accurate certificate details are critical to confirming the signer’s authenticity.

Revocation info is missing

In some cases, the app tries to check if a certificate has been revoked but can’t access the necessary data. Without that confirmation, the signature status remains unclear. This doesn’t always mean the certificate is bad—but it does mean you should proceed with caution.

If you’re unsure, the iLovePDF Desktop app will usually tell you which of these issues is causing the problem.

Are digital signatures legally binding?

The short answer is yes—digital signatures are legally binding in many countries around the world. However, for a digital signature to hold up legally, a few important conditions need to be met. Here’s what makes a digital signature legally valid:

Everyone agrees to use them

All parties involved must consent to using electronic signatures instead of traditional handwritten ones. Many digital signing platforms include a consent step to make this agreement clear before signing.

The signer’s identity is confirmed

It’s crucial that the person signing the document can be clearly identified. A verified digital certificate tied to the signature helps ensure that the identity of the signer is trustworthy and traceable.

The document hasn’t been altered after signing

For a digital signature to remain valid, the content of the document must stay exactly the same after it’s signed. If any changes are made, the signature becomes invalid—protecting the integrity of the agreement.

The signature complies with local laws

Different regions have specific laws and standards for digital signatures. For example, the eIDAS Regulation in the EU and the ESIGN Act in the U.S. outline how digital signatures must be created and verified to be legally binding.

Qualified electronic signatures (QES) carry the highest legal weight

In the European Union, a Qualified Electronic Signature (QES) represents the highest standard. A QES is backed by a qualified certificate issued by a recognized trust service provider, and it holds the same legal weight as a handwritten signature in court.

Final thoughts: simple steps to stay secure

Digital signatures add a strong layer of protection to your documents—but only if you know how to read them. With the iLovePDF Desktop app for Windows, you can quickly check if a signature is valid, spot problems, and revise your certificates when needed.

If something looks off, trust your instincts and double-check the certificate details. A few clicks can save you a lot of confusion (or worse) down the line.

Want to learn more?

Check out our other articles relate to e-Signing:

• What is a wet signature? A comparison with digital signatures
• Digital signatures and trust: Navigating the eIDAS Regulation
• What is the ESIGN Act? e-Signature compliance explained
• eSign with iLovePDF: Managing & tracking signature requests

Start checking your digital signatures with confidence—no technical background needed

Download iLovePDF Desktop